Asphaltic composition and process of making the same



p sta Jan. 2, 1945 ASPHALTIC COMPOSITION AND PROCESS OF MAKING THE SAMEStanley S. Sorem, Berkeley, Calif., assignor to Shell DevelopmentCompany, San Francisco, CaliL, acorporation of Delaware No Drawing.Application Juneis, 1942, e

Serial No. 446,999

12 Claims. (c1. 19c-22) This invention relates to hard fusibleas'phaltic compositions which are solid at ordinary temperatures,substantially completely soluble in carbon disulfide, possess meltingtemperatures of about 700 F. or above, are less than 5% volatile" asdetermined by A. S. T. M. test D-6-39T, and consist largely ofasphaltenes and petrolenes.

Petrolenes, as herein defined, are hydrocarbons of th type normallyassociated with asphalts. They possess relatively high boilingtemperatures and are soluble in 88 B. naphtha. They are normally solidor liquid and have Watson characterization factors normally below about11.5

(see article Symposium on physical properties of hydrocarbon mixtures byWatson et al. in Ind. 81 Eng. Chem., vol; 25, N0. 26, August 1935, page881). Included are various hydrocarbon oils boiling higher thankerosene, i. e. gas oils,

light and heavy lubricating oils of relatively low viscosity indexes, e.g. below about 70, or extracts thereof, petroleum resins, albinoasphalts, etc. Excluded are paraflln wax, petrolatum, highly parailiniclubricating oils, etc. for use by themselves, e. g. alone and not inadmixture with suitable petrolenes.

Asphaltenesare normal constituents of asphalts which are soluble'incarbon disulfide, pyridine, chloroform or benzene, but are insoluble in88 B. naphtha. They are black or brown, normally solid, hard andbrittle;have penetrations of "approximately 0- (see Abraham's Asphalts andAllied Substances, 4th ed., D. Van Nostrand 8; Co., 1938); and areeasily reduced to a dry powder. Asphaltenes occur naturally or may beproduced by oxidation of petrolene as by air blowing at elevatedtemperatures of about 450 F., reaction with sulfur or chlorine, etc.Chemically, they are believed to consist predominantly of saturated orunsaturated aromatic or naphthenic polynuclear hydrocarbons of highcarbon-to-hydrogen ratios.

The asphaltic composition of this invention differs from pyrobituminousmaterials such as petroleum coke, bituminous coal, pure asphaltenes andthe like, in that the former, when heated,

melts without decomposing. It differs from petroleum asphalts (includingblown petroleum asphalts) and natural asphaltites such as gilsonite,glance pitch, grahamite, etc., in that the latter compounds containlower percentages of asphaltenes, possess softening or meltingtemperatures -(the highest below about 600 F.) substantially below themelting temperature of the composition of this invention, and are morevolatile.

The object of this invention is to produce a new hard asphalticcomposition having a high melting temperature and containing less than5% volatile material.

Another object is to produce a substitute for friction modifiers suchasdrying oil resins employed in friction element compositions. Anotherobject is to produce a new asphaltic thermoplastic compound. A furtherobject of this invention is to prepare such an asphalt composition by anew, simple and"economical-method.

The composition of this invention is manufactured by treatingintermediate petroleum asphalts having certain properties with asuitable solvent under certain conditions, which are described later.

Suitable intermediate petroleum asphalts have melting temperatures aboveabout 300 F., pene-' trations of less than 1, and are substantiallycompletely soluble in carbon disulflde, pyridine, chloroform or benzene.They contain from about 55% to 85% by weight asphaltenes, and about 45%to 15% by weight petrolenes. Substantial ly completely soluble" asherein used means at least 98% soluble and preferably 99/z% soluble inthe solvents, the remaining insoluble portions being. impurities such asfree carbon and min-v eral matter.

These intermediate asphalts-may be obtained from asphaltic crudes orfrom cracked residues by distillation, precipitation and/or -oxidation.Precipitated asphalts are generally produced by extracting thenon-.asphaltic constituents from a topped crude or cracked residue bymeans of a hydrocarbon solvent such as a parafiinic hydrocarbon liquidof less than 6 carbon atoms, e. g.

casinghead gasoline, liquid butane, liquid propane, etc. Distilled orprecipitated asphalts may be further oxidized to increase their meltingtemperatures, if too low, as by blowing them with air at an elevatedtemperature, preferablyv between about 450 F. and 500 F.

Suitable solvents for the treatment of the intermediate asphalts mustpossess preferential solvent powers for petrolenes but not asphaltenes.Particularly useful are low boiling petroleum parafiinic naphthas havinga B. gravity of 60 or higher. It is important that the hydrocarboncentage of petrolenes in the product; also the solvent must not have toohigh a gravity or it would cause softening of the product, makingremoval of the solvent therefrom by filtration difflcult. Some eflectivesolvents include natural 1 to seconds, preferably'l to 5 seconds,sufligasoline, normal hexane. iscpentane. normal pentane. etc.Isopentane or isopentane fractions are preferred. "Isopentane iractions"as used herein tie defined to include low carbon mixtures which contain50% or more isopentaner a I Prior to' solvent treating. it is desirableto comminute theintermediate asphalts to insure intimate contactbetweenthe asphalt and the solvent. Comminution is preferably carriedout at a temperature below about 150 F. and is continued until theasphalt particles will pass through a ZO-mesh or finer screen.

- solvent treatmentmay be carried out by either-oi two methods. In thefirst, the solvent is contacted and commingled with a comminutedasphalt, for a short period of time, usually about cient to dissolve outonly a portion of the petro lenes therein and to raise the meltingtemperature of the asphaltto above about 700 1 An boiling hlrdroa'sedosaof this invention is a hard.--dark, solid material,

equilibrium condition between the particles and the solvent is notpermitted to be established.

The exact amount of petrolenes which must be extracted to result .inthedesiredmelting point varies considerably, depending 'upon theproperties'oi both the petrolenes and asphaltenes. The

pelrtiezllyextracted particles are then dried to remove the solventwhereby the. desired composition of this invention is obtained. a 'Inthe second method, the comminuted' asphalt is thoroughly contacted andcomming led with the hydrocarbon solventf until equilibrium between theasphalt particles and solvent is substantially established, whereby asubstantial portion of the petrolenes is estracted, which portion ismuch 75-98% (97% optimum) which may be groundto powder for use inmoldable'and plastic compositions. It has a penetration of substantiallyless than 1, a meltingtelnperature of about 700 F, or above, preferablybetween about 700 and 750 F., and is less than 5% by weight volatile bya s,- r, M. method D6-39Tn Owing to the fact that near the melt ingtemperature the asphaltic composition bechemical, and physicalproperties of petrolenes and/or asphaltenes, which may comprise fairlywide classesjoi dlflerent though related compounds. The apparatusemployed in preparing the asphaltic composition of this invention may beof any convenient or conventional type which will larger than thatremoved by the first method. I The insoluble portion is then separatedfrom the I extract and dried. A small amount of oily hy-' drocarbonsorpetrolenes is added to and thoroughly commingled with the resultingdried as-- phalt particles, which amount" is sufficient to produce acomposition having a melting temperature of above about 700 F.,preferably between about 700 and 750 F. Without the addition of thisoily material the'dried asphalt particles, consisting mostly ofasphaltenes,'would not melt without withstand the conditions necessaryfor producing the composition. -For example, the blowing ofa petroleumasphalt can be carried out in a conventional air-blowing still and theblown asphalt may be run into an open reservoir, from which it mayreadily be removed; comminutingwthe blown asphalt may beefiected in agrinder similar to a coal pulverizergcom'min'gling of theasdisintegration. The exact amount of petrolenes added varies, usuallybetween about 1%and 5% by weight, depending largely on the type ofpetro-- lenes used and the properties of the asphaltenes present. 1

4 The added oily hydrocarbons or petrolenes are liquids or plasticscompatible with the asphaltenes, having lower softening temperaturesthan the desired asphaltic composition, and comprising the heavierfractions of crude oil such as crude oil distillation residuessubstantially free from components boiling below about 600 F'., blowdown011 from petroleum coke boiling above about 600 F., and lubricating oilextracts from various hydrocarbon oils obtained by a selective solventhaving preferential solvent power for aromatic hydrocarbons or mixturescontaining them, etc. Extracts, as is known, areobtained, for example byextracting topped crudes, bright stocks, lubriphalt with the solvent maybe effected in a mixing tank, or a continuous, rotary or vacuum-filter;and drying of the asphalt may-be effected in a separate drier such as a,cone drier, wlferein steam may be used. The employment of othernecessary pieces of equipment, such as additional grinders, pumps,tanks, driers, filters and the like, is within the knowledge of anyoneskilled in the art.

The following specific examples disclose ways in which the particularasphaltic composition of this invention may be produced.-

Example! v A. Mid-Continent propane-precipitated" petroleum asphalt wasblown with air at 450 F. to

produce a blown asphalt having a melting temperature. of about 320 F.This material was ground in a mill so that all of it would pass 'catingor gas oils with sulfur dioxide, nitrobenzene, methyl acetate, phenylacetate, furfural,

acetone, aniline, phenol, cresyl'ic acids, beta- .beta'-dichlordiethylether, suliur dioxide-nitrobenzene mixtures, or other. selectivesolvents, or.

with a combination of solvent and anti-solvent,

such as phenol or cresol with propane, etc.

As indicated before, the asphaltic composition through a 20-mesh screen.This ground asphalt was deposited on a suction filter and washed oncewith 15 cc. of ,isopentane per gram of' ground asphalt. The washedasphalt was then thoroughly dried on the filter, producing ahard, drypowder having a melting temperature of about 700 F. and being less than5% volatile. The

isopentane employed for washing had the follow- 1118 4. s. T. M.distillation:

I! i A 6' A. P. I. gravity cracked residue was precipitated withgasoline using about 20 volumesof gasoline per volume of residue. Theresulting precipitate, comprising a large portion of asphaltenes, wasremoved with a centrifuge and washed once through on a filter with 1500.of isopentane per gram of precipitate. This precipitate was then driedover superheated. steam to produce an asphaltic composition having amelting temperature of about 700 F. and being less than 5% volatile.

. Example III A blown petroleum asphalt having a softening point of 326F. and an A. S. T. M. penetration of at 77 F. was crushed and mixed to aslurry with isopentane, and deposited on a suction filter in a layer /2to inch thick. The asphalt thus deposited was washed until free from allsoluble components or' petrolenes, leaving substantially only theasphaltenes on the filter. These resulting asphaltenes were'dried for anhour by blowing superheated steam at 400 F. through the filter.

high aromatic lubricating oil extract. To facilitate the dispersion ofthe extract 'in the asphaltenes it was dissolved in gasoline at aconcentration of about 15%. When this extract was combined with theasphaltenes, the gasoline therein was evaporated and the extractsaturated asphaltene particles were dried again with superheated steam,producing the asphaltic composition having a melting temperature ofabout 700 F. and being less than 5% volatile.

The asphaltic composition of this invention has several uses, one ofwhich is as a substitute-for drying oil resin in friction elements,namely brakeshoes, clutch faces and the like, wherein the heat offriction causes the material to soften and become rubber-like, therebyincreasing the friction co-eflicient of the brakeshoe. Another use is asa thermoplastic moldabie material. Also, its properties make it aneflicient extinguisher for incendiary bombs because the heat from theburning bomb melts the composition to form a blanket around the bombexcluding air from it, thus stopping its burning.

I claim as my invention:

1. An asphaltic composition fusible without decomposing, having. amelting temperature of about 700 F. or above and a volatility of lessthan 5%v at said temperature, and being substantially completely'solublein carbon disulfide and from 2% to 35% by weight soluble in isopentane.

2. An asphaltic composition fusible without decomposing, consistingessentially of asphaltenes and such an amount of petrolenes that thecomposition has a melting temperature of about 700 F. or above and isless than-5% volatile at said temperature said composition beingsubstantially completely soluble in carbon disulfide.

3. The composition of claim 2 wherein the melting temperature of thecomposition is between about 700 F. and 750 F.

carbon disulfide. from a petroleumasphaltihav- The dry asphaltenes werethen removed from the filter and mixed with about 3% of a meltingtemperature above about 300 F., and

substantially completely soluble in carbon disulfide, comprisingextracting said asphalt with an isopentane fraction for a period of timesuificient -to dissolve only a portion of the petrolenes therein but notto soften the particles, and drying said asphalt. I

7., A process forproducing an asphaltic composition fusible withoutdecomposing consisting essentially of asphaltenes and petrolenes, saidcomposition having a melting temperature of about 700 F. or above andbeing less than 5% volatile at said temperature, from a petroleumasphalt consisting essentially of asphaltenes and petrolenes, having amelting temperature above about 300 F. and substantially completelysoluble in carbon disulfide. comprising removing a major portion of saidpetrolenes therein and adding to the remaining asphaltenes a smallamount of an aromatic lubricating oil extract sufficient to produce saidcomposition having a melting temperature of above about 700 'F.

8. A process for producing an asphaltic composition fusible withoutdecomposing, having a melting temperature of between about 700 F.

and 750 F. and being less than 5% by weight volatile at saidtemperature, from a petroleum residue, comprising the steps of blowingsaid residue with air while in the liquid state to enrich it inasphaltenes and to produce an asphalt hav- 9. The process of claim 8wherein said residue is blown with air at a temperature of about 450 F.

10. The process of claim 8 wherein said period of time is between about1 and 5 seconds.

11. An asphaltic composition fusible without decomposing, consistingessentially of asphal tones and such an amount of petrolenes that thecomposition" has a melting temperature of about 700 F. or above andis-less than 5% volatile at said temperature, said petrolenes comprisingat least in part an aromatic lubricating oil extract.

12. An asphaltic composition fusiblewithout decomposing consistingessentially of asphaltenes and. petrolenes, said asphaltenes comprisingto 98% by weight of the composition and said petrolenes comprising 25%to 2% by weight of the composition, said composition having a meltingtemperature of about 700 F. or above, being less than 5% volatile atsaid temperature, and

being substantially completely soluble in carbon disulfide.

STANLEY S. SOREM.

